Effect of pulse shaping as a countermeasure for frequency selective fading

1994 ◽  
Vol 30 (5) ◽  
pp. 386-387
Author(s):  
E.E. Hassan
Keyword(s):  
Pulse Shaping ◽  
Selective Fading ◽  
Frequency Selective Fading ◽  
Frequency Selective

scholarly journals Analisis Unjuk Kerja Improved Sinc Power Pulse pada Sistem OFDM Melalui Kanal Frequency Selective Fading

2019 ◽  
Vol 18 (3) ◽  
pp. 323
Author(s):  
Kadek Agus Mahabojana Dwi Prayoga ◽  
NMAE Dewi Wirastuti ◽  
Nyoman Pramaita
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Pulse Shaping ◽  
Density Ratio ◽  
Pulse Frequency ◽  
Noise Power ◽  
Selective Fading ◽  
Frequency Selective Fading ◽  
Power Pulse ◽  
Noise Power Spectral Density ◽  
Frequency Selective

Kombinasi antara sistem OFDM (orthogonal frequency division multiplexing) dan Pulse Shaping mampu mengurangi Inter Carrier Interference (ICI) dan error yang terjadi. Penelitian ini bertujuan untuk mengetahui perbandingan performansi dari sistem OFDM tanpa pulse shaping dan OFDM dengan pulse shaping Improved Sinc Power (ISP) pulse yang melalui kanal Frequency Selective Fading, ditinjau dari BER (bit error rate) berbanding Eb/No (energy per bit to noise power spectral density ratio). Penelitian ini menggunakan metode simulasi dengan menggunakan program Matlab R2018a. Hasil dari simulasi didapat unjuk kerja sistem OFDM dengan pulse shaping ISP pulsememiliki hasil yang lebih baik dari OFDM tanpa pulse shaping. Pada kanal transmisi Frequency Selective Fading untuk mencapi nilai BER sebesar 10-1 sistem OFDM dengan pulse shaping ISP pulse dibutuhkan Eb/No sebesar 2 dB. Sedangkan pada sistem OFDM tanpa pulse shaping dibutuhkan Eb/No sebesar 10 dB. Kata Kunci — OFDM, Pulse Shaping, ICI, ISP pulse, Frequency Selective Fading.

Acoustic-based Upper Facial Action Recognition for Smart Eyewear

2021 ◽  
Vol 5 (2) ◽  
pp. 1-28
Author(s):  
Wentao Xie ◽  
Qian Zhang ◽  
Jin Zhang
Keyword(s):  
Frequency Domain ◽  
Orthogonal Frequency Division Multiplexing ◽  
Interaction Mechanism ◽  
Phase Changes ◽  
Experimental Result ◽  
Selective Fading ◽  
Time Frequency ◽  
Facial Action ◽  
Frequency Selective Fading ◽  
Frequency Selective

Smart eyewear (e.g., AR glasses) is considered to be the next big breakthrough for wearable devices. The interaction of state-of-the-art smart eyewear mostly relies on the touchpad which is obtrusive and not user-friendly. In this work, we propose a novel acoustic-based upper facial action (UFA) recognition system that serves as a hands-free interaction mechanism for smart eyewear. The proposed system is a glass-mounted acoustic sensing system with several pairs of commercial speakers and microphones to sense UFAs. There are two main challenges in designing the system. The first challenge is that the system is in a severe multipath environment and the received signal could have large attenuation due to the frequency-selective fading which will degrade the system's performance. To overcome this challenge, we design an Orthogonal Frequency Division Multiplexing (OFDM)-based channel state information (CSI) estimation scheme that is able to measure the phase changes caused by a facial action while mitigating the frequency-selective fading. The second challenge is that because the skin deformation caused by a facial action is tiny, the received signal has very small variations. Thus, it is hard to derive useful information directly from the received signal. To resolve this challenge, we apply a time-frequency analysis to derive the time-frequency domain signal from the CSI. We show that the derived time-frequency domain signal contains distinct patterns for different UFAs. Furthermore, we design a Convolutional Neural Network (CNN) to extract high-level features from the time-frequency patterns and classify the features into six UFAs, namely, cheek-raiser, brow-raiser, brow-lower, wink, blink and neutral. We evaluate the performance of our system through experiments on data collected from 26 subjects. The experimental result shows that our system can recognize the six UFAs with an average F1-score of 0.92.

scholarly journals Hybrid Beamforming for Terahertz Multi-Carrier Systems Over Frequency Selective Fading

2020 ◽  
Vol 68 (10) ◽  
pp. 6186-6199
Author(s):  
Hang Yuan ◽  
Nan Yang ◽  
Kai Yang ◽  
Chong Han ◽  
Jianping An
Keyword(s):  
Selective Fading ◽  
Frequency Selective Fading ◽  
Hybrid Beamforming ◽  
Frequency Selective ◽  
Carrier Systems

scholarly journals Performance Analysis of MIMO STBC System in Flat Fading and Frequency Selective Fading Channels

2019 ◽  
Vol 3 (1) ◽  
pp. 19
Author(s):  
Pebri Yeni Samosir ◽  
Nyoman Pramaita ◽  
I Gst A. Komang Diafari Djuni Hartawan ◽  
Ni Made Ary Esta Dewi Wirastuti
Keyword(s):  
Fading Channels ◽  
System Performance ◽  
Mimo System ◽  
Multipath Fading ◽  
Delay Spread ◽  
Selective Fading ◽  
Frequency Selective Fading ◽  
Flat Fading ◽  
Frequency Selective ◽  
Frequency Selective Fading Channels

Multiple Input Multiple Output (MIMO) technology is a technique that can be used to overcome multipath fading. The multipath fading is caused by signals coming from several paths that experience different attenuations, delays and phases. In a multipath condition, an impulse that sent by the transmitter, will be received by the recipient not as an impulse but as a pulse with a spread width that called delay spread. Delay spread can cause intersymbol interference (ISI) and bit translation errors from the information received. To determine the effect of delay spread on the MIMO system, then MIMO system performance research was performed on flat fading and frequency selective fading channels using the Space Time Block Code (STBC) coding technique. This research was conducted using MatLab 2018a software. The simulation results show that the MIMO STBC system performance on flat fading channels is better than the MIMO STBC system performance on the frequency selective fading channel. This result is analyzed based on the value of BER vs. Eb/No and eye diagram.

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